The invention relates to systems and methods for detecting gas leaks such as methane gas leaks.
A common means of distributing energy around the world is by the transmission of gas, usually natural gas. In some areas of the world manufactured gasses are also transmitted for use in homes and factories. Gas is typically transmitted through underground pipelines having branches that extend into homes and other buildings for use in providing energy for space and water heating. Many thousands of miles of gas pipeline exist in virtually every major populated area. Since gas is highly combustible, gas leakage is a serious safety concern. Recently, there have been reports of serious fires or explosions caused by leakage of gas in the United States as the pipeline infrastructure becomes older. For this reason, much effort has been made to provide instrumentation for detecting small amounts of gas so that leaks can be located to permit repairs.
Conventionally, search teams are equipped with gas detectors to locate a gas leak in the immediate proximity of the detector. When the plume of gas from a leak is detected, the engineers may walk to scan the area slowly and in all directions by trial and error to find the source of the gas leak. This process may be further complicated by wind that quickly disperses the gas plume. Such a search method is time consuming and often unreliable, because the engineer walks around with little or no guidance while trying to find the source of the gas leak.
Another approach to gas leak detection is to mount a gas leak detection instrument on a moving vehicle, e.g., as considered in U.S. Pat. No. 5,946,095. A natural gas detector apparatus is mounted to the vehicle so that the vehicle transports the detector apparatus over an area of interest at speeds of up to 20 miles per hour. The apparatus is arranged such that natural gas intercepts a beam path and absorbs representative wavelengths of a light beam. A receiver section receives a portion of the light beam onto an electro-optical etalon for detecting the gas.
Although a moving vehicle may cover more ground than a surveyor on foot, there is still the problem of locating the gas leak source (e.g., a broken pipe) if a plume of gas is detected from the vehicle. Thus, there is still a need to provide a method and apparatus to locate the source of a gas leak quickly and reliably.